Sony Ericsson T637

AT&T Mmode Button

Have had the T637 for over a week now -- best phone I've ever had. One problem -- AT&T (my service provider) has changed the right soft menu button on the phone to an 'Mmode' button. I believe the normal state of this button when a carrier isn't involved is 'More' -- so it yields other options.

I rarely use Mmode (slow as death), and want to get it off my main screen. Does anyone know how to change/hack the setting to get it back to its default state?